1. Field of the Invention
This invention relates to a cleansing processing agent for cleansing harmful substances contained in waste materials, sewage water, exhaust gases or soil, and to a cleansing method.
2. Description of the Related Art
The resins containing styrene and/or conjugated dienes and acrylonitrile may be enumerated by styrene-based resins, such as ABS resins, SAN resins or AAS resins, and by synthetic rubber, such as NBR rubber.
These resins are relatively inexpensive. In particular, the styrene-based resins are excellent in toughness, dimensional stability or workability and hence are prevalently used as resin materials, such as covers or casings of various usages, casings of an electronic equipment or vehicles, or various component parts. The synthetic rubber, on the other hand, are prevalently used in tubes, hoses or as a variety of shock-absorbing materials. Under these circumstances, these materials are expected to be used in more extensive fields of application, while researches into higher added-value products are desired. On the other hand, the products formed of the above materials yield a large quantity of waste materials. Recently, the amount of the waste material tends to be increased, such that there exist increasing needs for effective utilization of waste materials.
Meanwhile, disposal of used-up plastics by incineration or land filling account for a major portion (approximately 90%) of the total amount of disposal, such that only a small fraction of the waste materials are being re-used by melting by heating. This recycling by melting by heating suffers from many problems, such as thermal deterioration, including lowering of the molecular weight, resin oxidation, or mixing of resins containing a variety of coloring agents in need of color matching, such that processing technology or cost present serious problems.
On the other hand, incineration produces toxic gases. Thus, under the present situation, one has to resort to processing by land filling. However, the amount of yielding of waste materials inclusive of waste plastics tends to be increased recently, such that direct disposal thereof by lad filling is inefficient and presents problems in nations in which the site suited for land filling is short. Moreover, environmental destruction by leakage of toxic substance, mainly heavy metals, from the land filling site, that is soil pollution, are attracting attention. These toxic substances induce pollution by mainly heavy metals in the waste materials leaking out with acidic rain.
As discussed above, plastic waste materials are yielded in increased amounts year by year, and attention is directed to effective utilization thereof, while there is also demanded the development of a technology of combatting the environmental pollution due to leakage of the harmful substances on disposal of the waste materials containing plastic waste materials.